Heat exchange apparatus



l 7, 1936. D, 1 HIGGINS 2,027,315 v HEAT EXCHANGE APPARATUS Filed March23, 1935 2 Sheets-Sheet l Miam-463 Jan. 7, 1936 D. HIGGINS, I 2,027,3l5

HEAT EXCHANGE APPARATUS Filed March 25, 1935 2 Sheets-Sheet 2 @Bgm YPatented Jan. 7, 1936 UNITED; STATES 4PATEN'I OFFICE 2,027,315 HEATEXCHANGE APPARATUS Dmagh Loring Higgins.

to B. F. Sturtevant Mass Dedham, Mass., assigner Company, Inc., Boston,

Application March 23, 1935, Serial No. 12,679

claims. (c1. 23a-12.3)

4. of the aeroplane is suspended a substantial distance below the wing.Since planes-of this type y at high altitude it is necessary that thepassenger space be heated. It has been obvious that the heat in theexhaust gases from one or more ot the` engines should be used forheating the y passenger space, but prior attempts to so utilize theexhaust heat have not been successful. It has been proposed, heretofore,in aeroplanes of this type, to produce steam by the heat in the exhaustof the engines, and to pass this steam through coils mounted in thepassenger space. The steam, however, condensedin the heating coils andit was not practical to return the condensate to the steam producingmeans because of the location of the engines and the exhaust manifoldsat a considerable height above the passenger space. Hot water or otherheating systems were not thought practical because of the diiliculty ofproviding suitable expansion chambers for the heating liquid, which itwas thought would be required, in View of the wide temperature rangesthat would be experienced in night, especially in view of the fact, thatan aeroplane of this type might be called upon to v from a tropical portin South America to a point which required the crossing of the AndesMountains. Then, too, it was not desirable to place heating coils withinthe cabin as had been proposed in the past.

According to this invention, a liquid having a high vaporizationtemperature and a low freezing point such as Prestone, is employed as aheat transfer medium. A plurality of extended surface heat exchangecoils, and an electrically driven' blower are arranged in a small streamlined housing, separating the cabin of the plane from the upper wing.'Ihe liquid is heated in coils, which are exposed to the heat from theexhaust from one or more of the motors and is circulated by a pumpthrough the extended surface coils and back again through the coilsexposed to the exhaust gases. The pump, uid lines and coils are notcompletely filled with the liquid, so that sumcient space is left inthese for the expansion of the liquid at high temperatures. One or moreducts are arranged longitudinally within the within the stream linedlnected to the pump heated in the coils |2, is, in operation,

cabin and the air is passed by the blower over the extended surfaceheating coils and into the ducts, which are provided with a plurality-ofspaced outlets from which the heated air is discharged into thepassenger space.

An object'of the invention is to provide a heat- 6 ing system forsupplying heated air to the passenger space of a high wing cabinaeroplane, utilizing heat'from the exhaust gases of the aeroplaneengines.

' 10 Another object of the invention is tb provide heat exchangeapparatus of the forced .draft type for heating the passenger space of ahigh wing cabin aeroplane; the apparatus being arranged between the wingof the cabin and the aeroplane.

-Other objects of the invention will be apparent from the followingdescription taken together with the drawings. f

'I'he invention will now be described with reference to the drawings of-whichzg 2 Fig. 1 is a plan view looking downwardly, with a portion insection, of an aeroplane equipped with heat exchange apparatus accordingto this invention; A

Fig. 2 is a sideview of the aeroplane of Fig. 1, 2 with a portion indotted outline Fig. 3 is a front view, with a portion in section, of theaeroplane of Figs. 1 and 2; and

Fig. 4 is a diagrammatic view of heat exchange apparatus installed inthe aeroplane. 3

High wing aeroplanes, especially, of the ying boat type have the wingspaced above the cabin. The space betweenthe wing and the cabin at thecentral point of the ycabin is iilled by the stream lined housing 5.arrangement, the engines are supported further from the water sprayproduced when the aeroplane is in contact with water and the cabin isfurther removed from the engines with reduced noise therefrom. Indesigning the heat exchange 4 system according to this invention, thespace compartment 5, is utilized for the blower 6, the electric motor 1,which drives the blower, the extended surface heat exchange coils 8, theliquid pump 9, and the electric motor 4 I0 for driving the pump.

The exhaust pipes II of two of the motors are wound with the coils I2,whi h in turn, are con- 9 and coils 8, so that liquid.

continu- 5 ously circulated through coils I2, pump 9 and heating coils8.

Arranged longitudinally within the cabin I3 of the aeroplane are the twolongitudinal dis- It is understood that with this 35 tribution ducts I4,which are connected to the such as "Prestone output side of the casingcontaining the heat exchange coils l. The space within the compartment icommunicates with the space within the cabin I3, and the blower 6 drawsin air from the space within the compartment- 5 and the space withincabin I3, the heated air being continuously recirculated. Due to thehigh speed of the aeroplane, there is sufilcient infiltration of freshair and exhaust of heated air, so that no provision for the heating offresh air and positive exhaust of heated air need be provided. The ductsIl are provided with the spaced discharge outlets I5 from which theheated air passes into the passenger space,

After many experiments, it was found that the above describedarrangement was the only one suitable for heating the air within thecabins of the high wing type aeroplanes, due as previously explained tothe fact that a liquid was used to partially lill the iluid lines. andto the selection and arrangement of the apparatus. The expansion of theheat exchange uld is taken care of, and the characteristics of the fluidare such that it does not solidify at low temperatures, nor vaporize athigh temperatures. Then, again, the heat exchange apparatus whichenables a forced draft of heated air to be produced is provided withoutencroachment upon the limited passenger space and without the productionof unpleasant noises.

Whereas, one embodiment of the invention has been described, for thepurpose of illustration, it should be understood that the invention isnot to be limited to the precise arrangement described as manydepartures will suggest themselves te those skilled in the art, afterhaving had access to this disclosure.

What is claimed is:

l. Heat exchange apparatus for an airplane having a cabin and having aninternal combustion engine mounted above said cabin, comprising a liquidcirculating system, containing a liquid havim a lower freezing point anda higher vaporination temperature than water, means in said system forheating said liquid withheat from the gases of said engine, air heatingcoils a pump in said system mounted below said heating means and betweensaid cabin and said engine, a blower for moving air over `said alla,means for passing recirculated air from add calin into said blower andmeans for `passing `the heated air leaving said coils into the passengu'.annee within said cabin.

2. Heat exdzange apparatus for an airplane having a ealllnand having aninternal combustion engine ymounted above said cabin, comprising aliquid circulating system, partially filled with a liquid having a lowerfreezing point and a higher vaporintion temperature than water, means insaid system for heating said liquid with heat from die exhaust gases ofsaid engine, air heating coils and a pump in said system mounted belowsaid heating means and between said cabin and said engine. a blower formoving air over said coils, means for passing recirculated air from saidcabin into said blower, and means for passing the heated air leavingsaid coils into the passenger space within said cabin.

3. Heat exchange apparatus for a high wing 5 cabin airplane, having anengine mounted above the cabin and having a relatively small streamlined compartment between the wing and cabin, comprising a liquidcirculating system containing a heat exchange liquid, Iraans for heatingthe liquid in said system with heat from the exhaust gases of saidengineat a point above said compartment, air heating coils in saidsystem mounted in said compartment, a pump for circulating the liquid insaid system, a blower for moving air over said coils, means for passingrecirculated air from said cabin into said blower, a duct having spacedopenings extending longitudinally above the passenger space in saidcabin, and means for passing the heated air leaving go said coils intosaid duct.

4. Heat exchange apparatus for a high wing cabin airplane, having anengine mounted above the cabin and having a relatively small streamlined compartment between the wing and cabin, 2.5 comprising a liquidcirculating system partially fllled with a heat exchange liquid having alower freezing point and a higher vaporization temperature than water,means for heating the liquid in said system with heat from the exhausta0 gases of said engine at a point above said compartment, air heatingcoils in said system mounted in said compartment, a pump for circulatingthe liquid in said system, a blower for moving air over said coilsmounted in said compartment, )l means for passing recirculated air fromsaid cabin into said blower, a duct having, spaced openings extendinglongitudinally of said cabin ,above the passenger space therein, andmeans for passing the heated air leaving said coils into 0 said duct atapoint substantially midway thereof.

5. Heat exchange apparatus for a high wing cabi'n airplane, having anengine mounted above the cabin and having a relatively small streamlined compartment between the wing and cabin, comprising a liquidcirculating system partially filled with a heat exchange liquid having alower freezingv point and a higher vaporization temperature than water,means for heating the liquid in said system with heat from the exhaustgases of said engine at a point above said compartment, air heatingcoils in said system mounted in said compartment, a pump for circulatingthe liquid in said system mounted in said compartment, a blower formoving air over said coils mounted in said compartment. means forpassing recirculated air from said cabin into said blower, a duct havingspaced openings extending longitudinally of said cabin above thepassenger space therein, and means for passing so the heated air leavingsaid coils into said duct at a point substantially midway thereof.

DARRAGH LORING HIGGINS.

